Cassette recorder that can take cassettes of various sizes

ABSTRACT

A cassette drive mechanism for cassettes wherein cassettes can be played back which have different sizes and for which different tape drive systems are otherwise required. By placing the different cassettes into a common cassette receiving device, the adaptation of the drive and tape scanning systems is automatically carried out at the side of the drive mechanism.

BACKGROUND

The invention relates to a cassette recorder which can selectivelyreceive cassettes of various sizes, in which the distance between thewinding plates receiving the reels of tape is variable. Such a recorderis known, cf. SMPTE Journal, August 1989, pages 568 to 574.

For selectively receiving cassettes of various sizes or various types ofcassette containing a recording medium in tape form, a distanceadjustment of the winding plates is provided in the known cassetterecorder. The selective driving of the winding-up plate, for exampleduring recording or reproduction of signals, or of the unwinding plate,for example during rewind operation of the device, is performed in eachcase by a winding plate motor driving the respective winding platedirectly.

The invention is based on the object of providing an inexpensiveadjustable winding drive.

This object is achieved by the invention specified in claims 1 and 15.Advantageous developments of the invention are specified in thesubclaims.

SUMMARY OF THE INVENTION

For the purpose of adapting the distance between the winding plates tothe respective rolls of tape of the respective type of cassette, theinvention is based on the idea of arranging the two winding plates suchthat they can swivel about a respective spindle, fixed relative to thedrive chassis of the cassette recorder, and, depending on the intendedtape-winding direction, of driving the respective winding plate, inengagement with a roll of tape, via a slip clutch.

Such a slip clutch can be realized in a simple way, for example byclutch wheels arranged rotatably on the respective winding-plate swivelspindle. The respective clutch wheels may in this case form part of thegear mechanism between the respective drawing winding plate and a drivemotor, or else also act or be used with their clutch Lining as awinding-plate brake.

With such stationary slip clutches, known per se, there is alsoassociated the advantage that, if using a swivel gear mechanism,likewise known per se, having a stationary central wheel and a swivelwheel which can be swivelled about the central wheel spindle and,depending on the intended tape-winding direction, automatically comesinto engagement with the one or the other slip clutch, or can beswivelled up against one of the clutch wheels of the respective slipclutch, only one motor is required for the driving of the two windingplates.

It is also conceivable to provide one central clutch instead of the twoslip clutches. Such a clutch can be realized in an advantageous way bythe swivel gear mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS

A cassette recorder according to the invention is explained below withreference to the drawings, in which:

FIG. 1 shows the drive side of a small type of cassette, by which thewinding plate spindles arranged rotatably on a drive chassis come intoengagement with the rolls of tape of the cassette.

FIG. 2 shows a sectional representation of the cassette according toFIG. 1,

FIG. 3 shows the drive side of the standard type of cassette,

FIG. 4 shows a sectional representation of the standard cassetteaccording to FIG. 3,

FIG. 5 shows, in a plan view of the drive mechanism, an adjustablewinding-plate drive,

FIG. 6 shows, in a plan view, the tape-winding plates in the operatingposition intended for the standard type of cassette,

FIG. 7 shows, in a plan view, the tape-winding plates in the operatingposition intended for the small type of cassette,

FIG. 8 shows in a sectional representation, in the region on theunwinding plate side, the slip clutch in engagement with the unwindingplate in the operating position intended for the small type of cassette,

FIG. 9 shows, in a sectional representation, a second exemplaryembodiment with a swivel gear mechanism which has a central clutch andis in engagement, via a stationary intermediate wheel, with theswivelling tape-winding plate on the unwinding plate side,

FIG. 10 shows a further sectional representation of the second exemplaryembodiment according to FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS(S)

It should also be pointed out that mutually corresponding parts areprovided with the same reference numerals in FIGS. 1-10.

FIG. 1 shows, in a diagrammatic representation, the drive side of anexemplary small type of cassette, which can be operated in the cassetterecorder according to the invention without the use of an adaptercassette.

As known, the drive side of this type of cassette has, like the largerexemplary standard type of cassette represented in FIG. 3, openings 1, 2for the cassette centering by means of pins (not shown) and alsoopenings for the engagement of the drive spindle of the respectivewinding plate 40, 41, shown in FIG. 5-FIG. 7, with the tape-windingelement 7, 8; 9, 10 assigned to it, a further opening 11; 12 beingprovided for the releasing of the two tape-winding elements 7, 8; 9, 10.For protection against unintentional recording over an existingrecording, the drive side has a coding opening 14. In addition,connections for a cassette identification may be provided on the rearside of the respective type of cassette.

Fig. 2 and FIG. 4 show, in a sectional representation, the tape-windingelement 7; 9 of the roll of tape of the respective type of cassette, onthe winding-up side.

With these two exemplary types of cassette according to FIG. 1 and FIG.3, it is intended at the same time to show that the invention is not inany way concerned only with the different types of cassette of a singlerecorder system standard, such as for example H8 or VHS.

For the operation or the loading of cassettes of different types, thereis preferably provided, furthermore, a drawer-like motor-driven loadingdevice, which is not represented. Such loading devices are known, inparticular from CD players. Into these is placed a cassette, the alreadymentioned centring pins coming into engagement with the two centringopens 1, 2, the distance between which is preferably the same in thecase of both types of cassette, and thereby providing cassette fixingduring the loading operation. During the loading operation, the cassetteloading device together with the placed-in cassette is transported intothe recorder in a drawing-in movement running essentially parallel tothe drive chassis 64 (FIG. 5) and is subsequently lowered over thewinding plates 40, 41. Depending on the type of cassette used, in thecassette loading position the two winding plates 40, 41 in this caseassume the position shown in FIG. 5 or FIG. 6, or the position shown inFIG. 7, the winding plate position for the small type of cassette beingrepresented in FIG. 7.

FIG. 5 shows, in diagrammatic representation in plan view, the drivechassis 64 of a cassette recorder with adjustable winding-plate drivefor the operation of different types of cassette.

The cassette recorder may, for example, be a video recorder with arotating head drum 23 which, during recording or playback operation, haswrapped around it the recording medium 22 in tape form, mounted in acassette 35 on reel elements 9, 10. The manner represented in which therecording medium 22 is unthreaded from the cassette 35 and in engagementwith the head drum 23 is known as C loading. The driving of therecording medium 22 takes place by means of a pinch roller 24 and thecapstan, driven by the capstan motor 25.

The capstan motor 25 is preferably also used at the same time fordriving the two winding plates 40, 41. The driving takes place via afixed central wheel 47, which is driven by belts 46, is in engagementwith a so-called swivelling idler wheel 48 and forms with the idlerwheel 48 a swivel gear mechanism. Depending on the direction of rotationof the motor 25, either the winding-up plate 41 or the unwinding plate40 is driven, via a respective slip clutch 44, 45. The engagement of theswivelling idler wheel 48 with the slip clutch 45, which corresponds tothe device operating mode of recording, playback or forward searchoperation, is represented. The structure of the respective fixed slipclutch 44, 45 is described in more detail in FIG. 8. The respectiveswivelling range of the two winding plates 40, 41 for the operation ofthe standard type of cassette or the small type of cassette isrepresented by circle sectors 30, 31.

Since the respective slip clutch 44, 45 is fixed, a tape-tension sensingbrake with a braking band 49, acting on the unwinding plate 40 and knownin particular from home video recorders, may advantageously be used.During recording or playback operation, the braking band 49 acts on theslip clutch 44 on the unwinding side, this band being controlled in aknown way by a tape-tension sensor 491 in engagement with the recordingmedium 22.

Instead of the capstan motor 25, other motors may also be used for thedriving of the swivelling winding plates 40, 41, for example separatemotors which drive the winding plates 40, 41 directly, or else also aseparate motor which drives the winding plates 40, 41 by means ofcentral wheel 47, idler wheel 48 and slip clutches 44, 45. Suchsolutions can, for example, be advantageously realized in the case ofdrive mechanisms in which it is provided to arrange the circuits for theservo and sequence control systems of the drive mechanism on a circuitboard, which is then arranged on the drive mechanism, for exampleunderneath chassis 64. In the case of such a drive mechanism, the statorof these motors may also be arranged on the circuit board in acost-saving way.

FIG. 6 shows, in diagrammatic representation in plan view, the twotape-winding plates 40 and 41, or unwinding plate 40 and winding-upplate 41, in the operating position intended for the standard type ofcassette, while FIG. 7 shows the operating position intended for thesmall type of cassette. As support, fixed supporting points 62, 63 areprovided for the standard cassette. The supporting points for the smalltype of cassette are formed respectively at the end of two swivel levers58, 59, which are arranged to the sides of the winding plates 40, 41such that they can swivel on a respective fixed pivot spindle 18, 19 andare in engagement by toothings with a slide 52. Corresponding regionsfor such supporting points are represented on the drive side of therespective type of cassette according to FIG. 1 and FIG. 3 by faces 3,4, 5, 6.

By means of the slide 52, which is guided in a guide 34, which isprovided in a top plate 65 arranged parallel to the chassis 64, both theposition of the two winding plates 40, 41 and the position of the twoswivel levers 58, 59 can be correspondingly set for the purpose ofadaptation to the different types of cassette. The setting of the twoswivel levers 58, 59 is effected by the abovementioned toothings. Withthe setting of the swivel lever 59 on the winding-up plate side, at thesame time cassette identification contacts 66 are adjusted, or swivelledabout the fixed pivot axis 19, such that these contacts can come intoengagement with the respective cassette identification 13 on the rearside of the cassettes according to FIG. 1 or FIG. 3.

For adjusting the tape-winding plates 40, 41 into the operating positionshown in FIG. 7 and back into the operating position shown in FIG. 6,the slide 52 can be mechanically connected to the already mentionedcassette loading device (not represented), so that the slide 52 can beautomatically actuated if a cassette of the small type of cassette isplaced into the cassette loading device and the loading operation isbegun. Such a mechanical connection can be realized in the cassetteloading device by simple mechanical means, to be actuated manually orelse automatically. As soon as the cassette reaches its respectiveloading position, i.e. comes into engagement with the winding plates 40,41, the already mentioned centring pins (not represented), by which thecassette is already fixed during the loading operation, also come intoengagement with corresponding positioning openings 32, 33 which arearranged on the top plate 65, and consequently position the cassette onthe drive chassis 64.

The swivelling of the winding plates 40, 41 takes place by the slideplate 52, which also contains the winding-reel release 53, with the aidof swivel levers 42, 43 (FIG. 8) bearing the winding plates 40, 41 inthat bolts 54, 55, arranged on the slide plate 52, engage into slots 56,57, which are formed in these swivel levers 42, 43.

FIG. 8 shows in sectional representation, in the region on the unwindingplate side, the slip clutch 44 in engagement with unwinding plate 40, inthe operating position intended for the small type of cassette accordingto FIG. 7.

The slip clutch 44 essentially comprises a first clutch wheel 50, whichhas the braking band 49 mentioned wrapped around it, a second clutchwheel 501, a preferably felt-like annular first clutch disc 502 betweenfirst clutch wheel 50 and second clutch wheel 501, which is inengagement with the swivelling idler wheel 48 by means of toothings whenthe unwinding plate 40 is driven, and a third clutch wheel 505, which isalways in engagement with swivelling unwinding plate 40 by means oftoothings, and also a prestressed spiral spring 504 and a second annularclutch disc 503 between second clutch wheel 501 and third clutch wheel505.

It should be pointed out that, apart from the braking band 49, therepresentation according to FIG. 8 also applies correspondingly to theregion on the winding-up plate side.

The winding-up plate 40 is mounted on a pivotable, swivel lever 42 whichis bent in the shape of a U and the pivot point of which is formed bythe fixed spindle 20 of the slip clutch 44. Pivotably mounted on thespindle 20 are the clutch elements 50, 501, 502, 503, 504 and 505. By avertical adjustment (not represented) of the idler wheel 48, the lattercan be brought into engagement with the third clutch wheel 505 andtransmit the driving torque directly to the winding plate 40.

In addition to the braking band 49, for tape-tension control there mayalso act on the clutch wheel 50 main and auxiliary brakes (notrepresented).

FIG. 9 diagrammatically shows, in sectional representation, a secondexemplary embodiment, with a swivel gear mechanism 147, which has acentral clutch and is in engagement, via a stationary intermediate wheel144, with the tape-winding plate 40, which is on the unwinding plateside and can be swivelled about the intermediate wheel spindle.

The second exemplary embodiment differs from the first exemplaryembodiment according to FIG. 5 and FIG. 8 essentially only in that,instead of the slip clutches 44, 45, a central clutch in the swivel gearmechanism 147 and intermediate wheels are provided, the operatingposition for the large type of cassette and the standard type ofcassette being represented in FIG. 9 and FIG. 10, respectively, with theintermediate wheel 144 on the unwinding plate side.

The swivel gear mechanism 147 essentially comprises an idler wheel 48,which can be swivelled about the stationary swivel gear mechanismspindle 70, a concentrically arranged central wheel 47, a concentricallyarranged cup-shaped drive wheel 74 and a central clutch, which isessentially formed by a concentrically arranged clutch ring 75, a firstfelt ring 73, arranged between the clutch ring 75 and the cup-shapeddrive wheel 74, a second felt ring 72, arranged between the cup-shapeddrive wheel 74 and the central wheel 47, a concentrically arrangedspiral-shaped compression spring 83, a concentrically arrangedadjustment ring 77, a concentrically arranged carrying disc 78, aconcentrically arranged driving disc 79, a concentrically arrangedlifting cam 80 and a concentrically arranged adjusting ring 81. For themounting of the swivel gear mechanism 147, there is provided on thedrive chassis 64 a carrying plate 82, which is arranged underneath thedrive chassis 64 and runs parallel to the latter.

The felt rings 72 and 73 form with the central wheel 47, the drive wheel74 and the coupling ring 75 a slip clutch, the action of which can beset by means of the adjustment ring 77, which is adjustable in the axialdirection of the swivel gear mechanism, by means of the driving disc 79,which is adjustable in the axial direction, and by means of thecompression spring 83, which is adjustable in the axial direction. Thecompression spring 83 is prestressed. The setting of the action of theslip clutch can be used to set, and consequently adapt, the drivingtorque, for example corresponding to the wound diameter of the roll oftape on the winding-up or drawing tape plate, in order to keep the tapetension in a permissible range during play operation.

The setting of the respective action of the slip clutch, andconsequently of the respective driving torque, takes place by turningthe adjusting ring 81 and the driving disc 79. The turning, for whichpreferably a turning range of about 120° is provided, takes place bymeans of the threading motor (not represented) via a toothed-wheel gearmechanism (likewise not represented), which is in engagement with thecorresponding toothing on the outer circumference of the adjusting ring81. When the adjusting ring 81 is turned, the driving disc 79 is moved,by means of the lifting cam 80 formed in the manner of a ramp on itscircumference, together with carrying disc 78 and adjustment ring 77 inthe axial direction of the swivel gear mechanism 147, whereby thecompression spring 83 is stressed more or less, depending on thedirection of movement, so that a torque dependent on the stressing ofthe compression spring is transmitted to the central wheel 47. In thisrespect, the "search backward" device operating mode is represented inFIG. 9. With the adjustment ring 77, an adjustment of the slip clutchcan be carried out. The adjustment takes place by an adjustment orturning of the adjustment ring 77, which, on account of a ramp-likeformation on the carrying disc 78, thereby effects a movement of theadjustment ring 77 in the direction of the swivel gear mechanism spindle70. As in the case of the first exemplary embodiment according to FIG.5, the driving likewise takes place by means of the capstan motor 25 viaa belt 46, which is in engagement with the cup-shaped drive wheel 74.

For rewinding operation, in which a greater driving torque is required,a bridging of the slip clutch is provided. According to FIG. 10, whichshows a further sectional representation of the second exemplaryembodiment, the adjustment ring 77 is lowered, by adjustment of theadjusting ring 81, to such an extent that detents 771, which are formedon the said adjustment ring and engage into cutouts of the clutch ring75, additionally engage into clearances of a blocking ring 76, which isconnected in a rotationally fixed manner to the drive wheel 74. Sincethe coupling ring 75 is guided in grooves formed parallel to the swivelgear mechanism spindle 70 on the shank of the central wheel 47, and thedrive wheel 74 is inter-connected with the clutch ring 75 by the detents771, the driving takes place from the drive wheel 74 via the detents 771and the clutch ring 75 directly onto the central wheel 47.

As represented in FIG. 9 and FIG. 10, the intermediate wheel 144 on theunwinding side has a circumferential groove, this groove being providedfor a braking band 49, which is represented in FIGS. 5 and 8 and servesfor the tape-tension control known per se.

We claim:
 1. Cassette recorder which can selectively receive cassettesof various sizes, in which the distance between winding plates receivingthe reels of tape is variable, comprising the winding plates are thesame for the respective cassettes of various sizes, and in each case awinding plate lies with its circumference in contact with thecircumference of a slip clutch serving as a drive, and can be swivelledabout a pivot spindle of the slip clutch, maintaining its contact withthe slip clutch.
 2. Recorder according to claim 1, wherein the slipclutch is formed by fixed clutch wheels, which are mounted rotatably ona chassis and has a friction lining.
 3. Recorder according to claim 1,wherein between two slip clutches, assigned to the two winding plates,there is mounted a central wheel, which serves as a drive for thewinding plates and can be coupled selectively with the first or secondslip clutch.
 4. Recorder according to claim 3, wherein between thecentral wheel and the two slip clutches there is mounted an idler wheelin such a way that it can swivel with the effect that it couples thecentral wheel selectively with the first or second slip clutch. 5.Recorder according to claim 3, wherein the clutch wheel of the slipclutch is assigned a tape-tension sensor with a braking band. 6.Recorder according to claim 1, wherein on a chassis there isdisplaceably mounted a slide plate, which engages at opposite ends aprojection, into a slot of a swivel lever swivel-mounted on the chassisand carrying a winding plate.
 7. Recorder according to claim 6, whereinthe slide plate is provided at opposite ends in each case with a toothedrack, into which a toothed rim in the form of a pitch circle engages forthe swivelling movement of swivel levers swivel mounted on the chassis.8. Recorder according to claim 7, wherein the swivel lever has anupwardly protruding projection, which forms a supporting point for theplaced-in cassette.
 9. Recorder according to claim 6, wherein each slideplate has an upwardly pointing projection, which engages into an openingof placed-in cassette housing and serves in a cassette housing forreleasing a winding interlock provided there to prevent turning of thereels of tape.
 10. Recorder according to claim 1, wherein a centralwheel is connected to a capstan motor via a drive belt.
 11. Recorderaccording to claim 1, wherein a central wheel is assigned a separatedrive motor.
 12. Recorder according to claim 1, wherein the swivellingmovement of the winding plate (40, 41) about the slip clutch is about90°.
 13. Recorder according to claim 1, wherein the slip clutches areassigned separate drive motors.
 14. Recorder according to claim 1,wherein the slip clutches are assigned a common drive motor that can bebrought into engagement selectively with one of the slip clutches. 15.Cassette recorder which can selectively receive cassettes of varioussizes, in which the distance between a winding plates receiving thereels of tape is variable, wherein a winding plates are the same for therespective cassettes of various sizes, and in that for driving thewinding plates there is provided a swivel gear mechanism, which has acentral clutch for torque transmission.
 16. Recorder according to claim15, wherein the central clutch has an adjustable slip clutch fortransmitting different driving torques.
 17. Recorder according to claim15, wherein means are provided for bridging a slip clutch.